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  2. Mass–luminosity relation - Wikipedia

    en.wikipedia.org/wiki/Massluminosity_relation

    The relationship is represented by the equation: = where L ⊙ and M ⊙ are the luminosity and mass of the Sun and 1 < a < 6. [2] The value a = 3.5 is commonly used for main-sequence stars. [ 3 ] This equation and the usual value of a = 3.5 only applies to main-sequence stars with masses 2 M ⊙ < M < 55 M ⊙ and does not apply to red giants ...

  3. Mass-to-light ratio - Wikipedia

    en.wikipedia.org/wiki/Mass-to-light_ratio

    Mass-to-light ratios in application can be used to gain insight into the dark matter content and dust extinction in a galaxy. [4] Historically, rotation curves for spiral galaxies have been used to study galaxies, but mass-to-light ratios prove more accurate as a method of measuring mass. [5]

  4. Galaxy color–magnitude diagram - Wikipedia

    en.wikipedia.org/wiki/Galaxy_color–magnitude...

    A preliminary description of the three areas of this diagram was made in 2003 by Eric F. Bell et al. from the COMBO-17 survey [1] that clarified the bimodal distribution of red and blue galaxies as seen in the analysis of Sloan Digital Sky Survey data [2] and even in de Vaucouleurs's 1961 analyses of galaxy morphology. [3]

  5. Tully–Fisher relation - Wikipedia

    en.wikipedia.org/wiki/Tully–Fisher_relation

    The Tully–Fisher relation for spiral and lenticular galaxies. In astronomy, the Tully–Fisher relation (TFR) is a widely verified empirical relationship between the mass or intrinsic luminosity of a spiral galaxy and its asymptotic rotation velocity or emission line width. Since the observed brightness of a galaxy is distance-dependent, the ...

  6. Initial mass function - Wikipedia

    en.wikipedia.org/wiki/Initial_mass_function

    For example, the initial mass of a star is the primary factor of determining its colour, luminosity, radius, radiation spectrum, and quantity of materials and energy it emitted into interstellar space during its lifetime. [1] At low masses, the IMF sets the Milky Way Galaxy mass budget and the

  7. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    The observational result of Hubble's law, the proportional relationship between distance and the speed with which a galaxy is moving away from us, usually referred to as redshift, is a product of the cosmic distance ladder. Edwin Hubble observed that fainter galaxies are more redshifted. Finding the value of the Hubble constant was the result ...

  8. Freeman law - Wikipedia

    en.wikipedia.org/wiki/Freeman_Law

    According to Brada and Milgrom, [7]. The acceleration constant of the modified dynamics (), a 0, appears in various predicted regularities pertinent to galaxies.For example, it features as an upper cutoff to the mean surface density (or mean surface brightness translated with M/L) of galaxies, as observed and formulated in the Freeman law for disks, and of the Fish law for ellipticals.

  9. Sérsic profile - Wikipedia

    en.wikipedia.org/wiki/Sérsic_profile

    Discs of spiral galaxies, such as the Triangulum Galaxy, have low Sérsic indices and a low degree of central concentration. Most galaxies are fit by Sérsic profiles with indices in the range 1/2 < n < 10. The best-fit value of n correlates with galaxy size and luminosity, such that bigger and brighter galaxies tend to be fit with larger n.